Method of burning sulphur and burner therefor



July 16, 1929. E, @MULLEN 1.720.742

METHOD OF BURNING SULPHUR AND BURNER THEREFOR Filed Nov. 11, 1925 2 Sheets-Sheet l L FRUM BLOWER INVENTOR [on/M J Mill-LEN WZCOWW E W A'TTORNEYS WITNESS July 16, 1929. E. J. MULLEN METHOD OF BURNING SULPHUR AND BURNER THEREFOR Filed Nov. 11, 1925 2 Sheets-Sheet 2 FROM BLOWER wm/zss i 4 INVENTOR Eon ml 1 flfuLLf/v A TTOR/VE Y8 Patented July 16, 1929.

UNITED STATES 1,720,742 PATENT OFFICE.

EDWIN J. MULLEN, OF NEW ROCHELLE, NEW YORK, ASSIGNOR TO GENERAL CHEMICAL COMPANY, OF'NEW YORK, N. Y., A CORPORATION OF NEW YORK.

METHOD OF BURNING SULPHUR AND BURNER THEREFOR.

Application filed November 11, 1925. Serial No. 68,261.

The invention relates to the art of burning sulphur, especially sulphur of the kind commercially known as brimstone. The object of the invention is to provide a novel method of burning the sulphur in which the heat resulting from the burning of the sulphur is utilized to distill or sublime subsequent quantities of the sulphur, and in which the sulphur dioxide gas produced is free from impurities originally present in the sulphur. The invention contemplates further the provision of a novel apparatus whereby the method may be efiiciently carried out. Other more specific objects will appear from the description hereinafter and the features of novelty will be pointed out in the claims.

In the accompanying drawings, which illustrate an example of the novel apparatus Without defining the. limits of the invention, Fig. 1 is a diagrammatic sectional elevation, Fig. 2 is a diagrammatic cross-section on the line 22 of Fig. 1, and Fig. 3 is a modification in the position of the melter.

The novel method consists in initially distilling or vaporizing a quantity of sulphur by means of a suitable heating agent, until suflicient vapor is supplied, the combustion (oxidation) of which will furnish the heat required for distilling subsequent quantities of sulphur. When this stage has been reached, the heat from the aforesaid heating agent is discontinued, and the heat furnished by the combustion of the sulphur vapor is utilized to distill subsequent quantities of the sulphur. In this manner the distillation and combustion can be carried on continuously without the use of externally supplied heat. The heat of combustion of the sulphur vapor is more than sufficient to supply the heat of vaporization of the subsequent quantities of sulphur to make the process continuous, and in fact, a considerable proportion of the sulphur vapors produced may be withdrawn be fore the combustion stage and only a portion burned, as the heat of combustion of a unit of sulphur is much larger than the heat required to vaporize it. In the preferred method air is mixed With the sulphur vapor in regulated amounts, whereby the heat generated and the rate of distillation can be closely controlled. Additional air is later added to completely burn the sulphur into S0 and to dilute the gas to the desired strength for subsequent operations. 4

The method may be advantageouslyv and efliciently carried out by means of the apparatus illustrated in the drawings. The apparatus referred to comprises a distilling chamber 10 through which a tube 11 passes as shown in Fig. 1, said tube extending beyond the distilling chamber 10 in opposite directions and at one end being provided With a lining of firebrick 12 forming a chamber 13; the latter converges toward an inlet opening 14 located in the wall at this end of the tube 11 and is provided with an opening 15 which communicates with a tubular extension 16 on the tube 11. The extension 16 permits a fuel such as charcoal to be introduced into the chamber 13 for the purpose of providing sufiicient heat by combustion to initially bring-the sulphur in the distilling chamber 10 to its boilin point. At this stage, sulphur vapor will egin to pass over from the distilling chamber into the combustion tube 11 and the heat of combustion generated here will be suflicient to continue the process.

It is to be understood that the preliminary heating means shown is only a preferred form and that other suitable means may be provided. The apparatus may be brought up to operating temperature by means of an oil or gas flame introduced into the combustion tube 11, or by any other suitable means.

A sleeve 18 is secured to one end wall of the tube 11 in registry with the inlet opening 14 and connected by means of a pipe 19 with the dome 20 located upon and communicating with the distilling chamber 10. The

function of the dome 20 is to free the sulphur vapor produced in the distilling chamber from any entrained sulphur mist. A nozzle 21. extends into the sleeve 18 in a direction to- Ward the inlet opening 14 and in registry therewith and is connected by means of a pipe 22 with a source of air under pressure, such as a blower or the like. A branch pipe 23 leads from the pipe 22 to an annular chamber 24 which surrounds the tube 11 near its opposite end and communicates therewith through the medium of slots 25 formed in the tube 11 as shown in Fig. 1. Suitable valves 26 and 27 may be provided in the pipes 22 and 23 respectively for the purpose of controlling the passage of air therethrough.

A pipe 28 connects the tube 11 with a melting chamber 29, the latter in turn communicating to the distilling chamber 10 by means of a pipe 30, which as shown in Fig. 1, has

its lower end located interiorly of the distilling chamber 10; a suitable valve 31 may be located in pipe 28 for controlling the flow of vapors therethrough. The melting chamber 29 is further connected, by means of a branchpipe 34, with a pi e 35 which leads from the exit end of the tube 11 and which is provided with a controlling valve 36.

As shown inFig. 1, a pipe 32 may extend from the pipe 28 to the distilling chamber 10 to connect these elements, a controlling valve 33 preferabl being located in said pipe 32, as illustrate A blow-off valve or drain 40 is located in the lower portion of the disdistilling chamber 10 as shown.

In the operation of the above described apparatus, combustion tube 11 and distilling chamber 10 are initially brought up to operating temperatures by means of an external heating agent, as by blowing air through a quantity of charcoal or other combustible material placed in the chamber 13, as above explained. A quantity of sulphur is initially vaporized in the distilling chamber 10 and passes upwardly into the dome 20 and thence over through the pipe 19 into the chamber formed by the sleeve 18. By the provision of the dome 20, providing for withdrawal of the sulphur vapor at a point considerably removed from the surface of the boiling sulphur, the vaporized sulphur is freed from any entrained sulphur spray or globules of molten sulphur and is thus in the form of substantial-- ly pure sulphur vapor. This sulphur vapor is mixed with a regulated amount of air and passed into the combustion tube 11. A portion of the sulphur vapors, depending upon the amount of air introduced, will burn to form S0,. The heat generated in this reaction in the tube 11 will pass into the sulphur in the distilling chamber 10 and cause it to boil, thereby forming additional sulphur vapor which will pass over into the tube 11, be burned, and furnish sufiicient heat to make the operation continuous. A portion of the hot vapors produced will pass through the pipe 28 through the melting chamber 29 and branch pipe 34 to thepipe 35 and there be added to the remainder of the vapors produced. As the hot vapors pass through the melting chamber 29 the sulphur therein is melted and inthis condition passes down through the pipe 30 into the distilling chamber 10.

It will be noted that in passingthrough said melting chamber, the hot vapors contact directly with the upper end of the pipe 30 whereby any tendency of the melted sulphur to congeal is prevented. It is to benhderstood that the means shown for melting the raw sulphur is only a preferred device for introducing raw sulphur into the distilling chamber 10, and that othermeans may be used. The advantage of this arrangement is that a constant level of sulphur is malntain'ed tilling chamber the reduction ditions which must necessarily be existent at the point of entry of the sulphur into the distilling chamber.

In practice 1t Wlll be found that the amount of air admitted through the nozzle 21 to give the temperature conditions and rate of distillation desired may not be sufficient to completely burn all of the sulphur vapor to S0,. The balance of the air, or in other words. the secondary air required to complete combustion and to dilute the gas to the predetermined strength desired for subsequent operations is by-passed through the branch pipe 23 into the annular chamber 24. and through the slots 25 into the tube 11 at a point on the other side of the distilling chamber 10 to that at which the initial combustion takes place. In this manner the secondary heat of combustion will not affect the rate of vaporiza- Moreover, a uniform tion in the distilling chamber 10, and a regulation of the strength of gas produced may be obtained independently of the rateof the said vaporization.

It is to be understood that either Oxygen, air, or any suitable gas containing oxygen may be used to burn the sulphur vapor. Where I have used the term oxygen in the claims I do not intend to limit myself to pure oxygen but intend to include air or other oxygen containing gas.

The pipe 28 through which a portion of the hot gases pass to the melter 29 may communicate with the tube 11 at any point subsequent to initial combustion. It is found advisable to have this connection adjacent to the zone of substantially complete combustion, in order that unburned sulphur vapor will not pass into the melting system and tend to clog it. When operating at low capacity the temperature of the gases leaving the initial combustion zone may be so low that any unburned sulphur therein will condense in pipe 28, melter 29, or pipe 34, and tend to clog the system. Under these conditions it will be found advisable to place the pipe 28 following the zone of secondary combustion, as shown in Fig. 3. In this arrangement the gases passing through the melter will be practically free of sulphur vapor, and the possibility of clogging will be prevented.

The provision of the nozzle 21 through which the air for initial combustion is admitted will give an effect similar to that of an injector and tend to produce a minus pressure in the distilling chamber 10. However. as vapor is constantly being produced in the disinpressure due to the injector effect is smalland not necessary for operation. The ressure produced by the boiling of the sulp ur is sufiicient to force "vapor over into the combustion tube without the necessity of applying suction. It has been found that any device suitable for mixing the sulphur vapor and air may be used instead of that shown. For this reason, the burner as illustrated and described will operate either under a plus or minus pressure. That is, the gases may be forced through the system either by a blower placed in the air supply line or by suction means placed in the exit line 35 through which the vapors produced pass to the process in which they are used. This passage of impurities from the raw sulphur into the sulphur dioxide gas produced is particularly noticeable in those types of sulphur burners in which the surface of the molten sulphur is subjected to agitation or drips from one level to another, as in the well-known rotary or shelf types of burners. Sulphur in the form of minute globules, or in the form of spray, is entrained in the gas stream and carries impurities from the raw sulphur into the sulphur dioxide gas produced.

In my process it will be noted that the raw sulphur is first distilled in the absence of oxygen and under conditions such that no burning to sulphur dioxide will take place, the sulphur vapor is then freed of entrained mist or spray, and the substantially pure vapor thus produced is then burned in a separate com bustion chamber. It has been found that a considerable portion of the impurities pres ent in raw sulphur, including arsenic, will remain behind in the distilling chamber 10 and not pass into the sulphur vapor and as even exceedingly small amounts of arsenic are detrimental to many processes in which S0 gas is used, as for instance, the contact process for the manufacture of sulphuric acid, the importance of my invention will be appreciated in that it permits the use of impure raw sulphur as the source of sulphur and yet gives an SO product substantially free of impurities. From time to time it will be found advisable to draw off any sediment which collects in distilling chamber 10 through the drain 40. This sediment will be found to contain a considerable proportion of the arsenic, dirt and other impurities present in the raw sulphur.

The connection 32 from the pipe 28 to the distilling chamber 10 has been provided to allow a portion of the hot gases to be passed over the surface of the sulphur and the distilling chamber 10. The gases introduced here will tend to blow sulphur vapors out of the distilling chamber and thereby increase the rate of vaporization. This affords a means in addition to the control of the amount of air for combustion for regulating the rate of vaporization and strength of gas produced. When utilizing this means of control, it will be found necessary to use an injector as the means of mixing the air and sulphur vapor,

in order to maintain the distilling chamber and connection 19 under a suction with reference to the pressure in the combustion tube, as it is obvious that gas will not flow through the connection 32 .into the distilling chamber unless the pressure in the distilling chamber is less than that in the combustion tube.

As the heat of combustion of only a portion of the vaporized sulphur is required to maintain the distillation process, it is clear that only that portion of the vaporized sulphur need be introduced at the'point of initial combustion as will be sutficient to supply the required heat. The remainder may be wit-hdrawn from the distilling chamber and used for any desired purpose or may be introduced into the combustion chamber at the point of secondary combustion.

With the novel method and the novel apparatus herein disclosed the heat developed by the combustion of vaporized sulphur is utilized to distill the sulphur and to maintain a supply of vaporized sulphur in the combustion chamber, thus doing away with the necessity for complicated heating plants and devices. The method and apparatus herein set forth thus enable the burning of the sulphur to be carried on in an efficient and economical manner.

By the term heat transfer relation as used in the claims I intend to include any relation of the distilling chamber and combustion chamber such that the heat generated by combustion of the sulphur is utilized to bring about distillation of the sulphur.

Various changes in the specific method and in the specific form of apparatus described and shown may be made within the scope of the claims without departing from the spirit of my invention.

I claim:

1. A sulphur burner comprising a sulphur distilling chamber, and a combustion chamber for burning the distilled sulphur extending through said distilling chamber.

2. In a sulphur burner, the combination of a sulphur melter, a distilling chamber connected therewith for vaporizing the melted sulphur, a combustion chamber extending through said distilling chamber, a conduit for conducting gases. from said combustion chamber to said melter, an injector connected with said combustion chamberfor injecting air into the same and a connection from said injector to the distilling chamber for permitting the passage of gas from said dist-illing chamber to said injector.

3. In a sulphur burner, the combination of a sulphur melter, a distilling chamber connected therewith for vaporizing the melted sulphur, a combustion chamber extending through said distilling chamber, a conduit connecting said combustion chamber with said distilling chamber, means in said combustion chamber for containing a combustible material for producing heat whereby the sulphur in said distilling chamber is initially sublimed, an injector connected with said combustion chamber for injecting air into the same, and a conduit for conducting secondary air to said combustion chamber at a point beyond its connection with the distilling chamber, for completing the burning of the sulphur vapors in said combustion cham- 4. The method of burning sulphur which consists in maintaining a supply of molten sulphur in a non-oxidizing atmosphere at a temperature sufiiciently high to vaporize said sulphur, conducting sulphur vapor produced from the molten sulphur to a point physically separated from and in heat transfer relation to the molten sulphur, and then burning the sulphur vapor whereby the heat of combustion of the sulphur vapor is utilized in vaporizing subsequent quantities of sulphur.

5. The method of producing a gas containing sulphur dioxide which comprises distilling sulphur to form a gas consisting of sulphur vapor, and the-n burning sulphur produced by such distillation in heat transfer relation to the sulphur undergoing distillation, whereby the heat of combustion of the sulphur is utilized in distilling subsequent quantities of sulphur and sulphur dioxide gas is produced substantially free from impurities originally present in the sulphur.

6. The process of producing a gas containdioxide which comprises distillto form a gas consisting substantially of sulphur vapor, and then burning said sulphur vapor with regulated amounts of oxygen in heat transfer relation to the sulhur undergoing distillation.

7. The method of producing a gas containing sulphur dioxide which comprises distilling sulphur under such conditions as to form a gas consisting substantially of sulphur vaor and containing practically no sulphur dioxide, and then burning said sulphur vapor in heat transfer relation to the sulphur undergoing distillation, whereby the heat of combustion of the sulphur vapor is utilized in distilling subsequent quantities of sulphur and sulphur dioxide gas is produced substantially free from impurities originally present in the sulphur.

8. The method of oxidizing sulphur to produce a gas containing sulphur dioxide free from impurities originally present in the sulphur which comprises distilling sulphur to produce a gas consisting substantially of sulphur vapor, freeing the sulphur vapor of sulphur spray entrained therein, and then generating the heat required for the distillation by burning said sulphur vapor in heat transfer relation to tillation.

ing sulphur ing sulphur ing the sulphur vapor the sulphur undergoing dis" 9. The method of oxidizing sulphur to produce a gas containing sulphur dioxide free from impurities originally present in the sulphur which comprises distilling sulphur to produce a gas consisting substantially of sulphur vapor, freeing the sulphur vapor of sulphur spray entrained therein, generating the heat required for the distillation by burning said sulphur vapor in heat transfer relation to the sulphur undergoing distillation, and melting the sulphur to be distilled prior to the distilling operation by additional heat generated in the oxidation of the sulphur vapor.

10. The method of oxidizing sulphur to produce a gas containing sulphur dioxide free from impurities originally present in the sulphur which comprises distilling sulphur to produce a gas consisting substantially of sulphur vapor, freeing the sulphur vapor,of sulphur spray entrained therein, generating the heat required for the distillation by burning said sulphur with regulated amounts of oxygen in heat transfer relation to the sulphur undergoing distillation, and completing the combustion of the sulphur vapor with oxygen at a point out of heat transfer relation to the sulphur undergoing distillation. 11. The method of oxidizing sulphur to produce a gas containing sulphur dioxide free from impurities originally present in the sulphur which comprises distilling sulphur to produce a gas consisting substantially of sul phur vapor, freeing the sulphur vapor of sulphur spray entrained therein, controlling the rate of distillation by burning said sulphur vapor with regulated amounts of oxygen in heat transfer relation going distillation, and completing the combustion of the sulphur vapor with regulated amounts of oxygen at a point out of heat transfer relation to the sulphur undergoing distillation to produce a sulphur dioxide gas of predetermined strength.

' 12. The method of oxidizing sulphur to produce a gas containing sulphur dioxide free from impurities originally present in the sulphur which comprises distilling a body of molten sulphur, withdrawing the sulphur vapor produced at a point removed from the surface of the molten sulphur to an extent such that the sulphur vapor is free of entrained spray, and generating the heat required for the distillation by burning the sulphur vapor in heat transfer relation to the sulphur undergoing distillation.

13. In a sulphur burner, the combination of means for distilling sulphur, means for free- 4 produced by distillation of entrained sulphur spray, and means for burning the sul hur vapor in heat transfer relation to said rst mentioned means.

14. In a sulphur burner,

means for. distilling sulphur, means for meltthe combination of 1 means for freeing the sulphur va or produced by distillation of entrained su phur spray, and means for burning the sulphur vapor in heat transfer relation to the distilling and melting means.

15. In a sulphur burner, the combination of a distilling chamber adapted to contain a body of molten sulphur, means for withdrawing sulphur vapor from said chamber at a point removed from the surface of the sulphur to an extent .such that the sulphur vapor will be free of spray, and a combustion chamber for burning the sulphur vapor connected to said means for withdrawing sulphur vapor, said combustion chamber being in heat transfer relation to said distilling chamber.

16. In a sulphur burner, the combination of a distilling chamber adapted to contain a body of molten sulphur, an inlet for molten sulphur in said chamber, a sulphur melter connected to said inlet, means forv withdrawing sulphur vapor from said chamber at a point removed from the surface of the molten sulphur and from said inlet to an extent such that the sulphur vapor will be free of spray, x

and a combustion chamber for burning the sulphur vapor connected to said means for Withdrawing sulphur vapor, said combustion chamber being in heat transfer relation to said distilling chamber.

17. In a. sulphur burner, the combination of a distilling chamber, means for freeing the sulphur vapor produced by distillation of entrained sulphur spray, a combustion chamber for burning the sulphur vapor in heat transfer relation to said distilling chamber, means for, supplying a regulated amount of'oxygen for the combustion, and means for supplying additional oxygen to complete the combustion of the sulphur vapor at a point beyond said distilling chamber.

18. In a sulphur burner, the combination of a distilling chamber adapted to contain a body of molten sulphur, an inlet for molten sulphur in said chamber, a sulphur melter connected to said inlet, means for withdrawing sulphur vapor from said chamber at a point removed from the surface of the molten sulphur and from said inlet to an extent such that the sulphur vapor is free of entrained spray, a combustion chamber for burning the sulphur vapor, said combustion chamber being in heat transfer relation to said distilling chamber and to said sulphur melter, an air supply conduit connected to said combustion chamber for supplyin controlled amounts of oxygen for the com ustion, and a second air supply conduit connected to said combustion chamber beyond said distilling chamber for supplying oxygen to complete the combustion of the sulphur vapor.

19. In a sulphur burner, the combination of a distilling chamber, a sulphur melter feeding into said distilling chamber, means for freeing the sulphur vapor produced by distillation of entrained sulphur spray, a combustion chamber extending through said distilling chamber for burning the sulphur Vapor, an air supply conduit connected to said combustion chamber for supplying oxygen for the combustion, means for regulating the amount of oxygen supplied, a second air supply conduit connected to said combustion chamber beyond said distilling chamber for supplying oxygen to complete the combustion of the sulphur vapor, and an exit conduit from said combustion chamber connected to said melter for passing hot gases from the combustion chamber through the melter to melt raw sulphur.

20. In a sulphur burner, a sulphur melter, a distilling chamber for vaporizing the melted sulphur, a combustion chamber extending through the distilling chamber, an air-supply conduit terminating in an injector for supplying air to said combustion chamber, a conduit connecting said melter and said distilling chamber and a conduit connecting said distilling chamber with a chamber surrounding said injector, an exit conduit connected with said melter for passing a portion of the gases of combustion through said melter from said combustion chamber to melt raw sulphur, a second air supply conduit connected to said combustion chamber beyond said distilling chamber for introducing air to further burn gases in said combustion chamber and a second exit conduit for withdrawing the remainder of the combustion gases.

In testimony whereof I have hereunto set 100 CERTIFICATE OF CORRECTION.

Patent No. 1,720, 742, Granted July 16, 1929, to

i EDWIN J; MULLER. It is hereby certified that, error appears in the printed specificationof the above numberedtpatent requiring correction as follows: Page 3, line 15, after the word "used" insert "In addition to obtaining a continuous supply of SO sub 2 gas mixture of any strength desired my process possesses the advantage not present in other types ofknown sulfur burners of permitting the use of impure raw sulfur and yet obtaining a pure S0 sub 2- gas containing exceedingly small amounts of impurities.- When raw sulfur is burned directly, arsenic, dirt or other impurities present in the sulfur will pass to a considerable extent into the S0 sub 2 produced, in some form. and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 10th day of September, A. D. 1929.

a M. J. Moore, (Seal) Acting Commissioner of Patents. 

